Narrative:

I was helping an avionics co-worker on a B737-300 to replace aircraft main battery. While I was busy in the aircraft electrical compartment removing the old battery; my co-workers went to the company's parts store where he was issued a pre-drawn battery and then brought it to me where I installed it (a pre-drawn part is a part that was previously assigned for a particular aircraft when a component is scheduled for a time change). I accomplished the installation and operations test as per maintenance manual; 'operations checked good.' 2 days later at an airport gate; a pilot reported low battery voltage on aircraft. An airline technician determined that the gate's power unit was bad and replaced the main battery. Upon examining the removed battery; he discovered that it was the wrong battery installed and it belongs to a B737-700. Contributing factors: 1) failure on my part to verify or recognize the wrong part number. 2) stores issuing wrong pre-drawn part for the wrong aircraft. 3) an experienced co-worker failed to recognize the wrong part number. 4) company parts compatibility system failed to filter the wrong part number when I entered the log page into the system. Corrective action: removal and replacement of the wrong battery. Filed an ASRS report. Perception: I thought that I installed the correct part and failed to doublechk the battery part number because I relied on stores and my experienced avionics co-worker to do the right thing.

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Original NASA ASRS Text

Title: MECHANIC REMOVED AND INADVERTENTLY REPLACED A B737-300 ACFT MAIN BATTERY WITH A BATTERY FOR A B737-700.

Narrative: I WAS HELPING AN AVIONICS CO-WORKER ON A B737-300 TO REPLACE ACFT MAIN BATTERY. WHILE I WAS BUSY IN THE ACFT ELECTRICAL COMPARTMENT REMOVING THE OLD BATTERY; MY CO-WORKERS WENT TO THE COMPANY'S PARTS STORE WHERE HE WAS ISSUED A PRE-DRAWN BATTERY AND THEN BROUGHT IT TO ME WHERE I INSTALLED IT (A PRE-DRAWN PART IS A PART THAT WAS PREVIOUSLY ASSIGNED FOR A PARTICULAR ACFT WHEN A COMPONENT IS SCHEDULED FOR A TIME CHANGE). I ACCOMPLISHED THE INSTALLATION AND OPS TEST AS PER MAINT MANUAL; 'OPS CHKED GOOD.' 2 DAYS LATER AT AN ARPT GATE; A PLT RPTED LOW BATTERY VOLTAGE ON ACFT. AN AIRLINE TECHNICIAN DETERMINED THAT THE GATE'S PWR UNIT WAS BAD AND REPLACED THE MAIN BATTERY. UPON EXAMINING THE REMOVED BATTERY; HE DISCOVERED THAT IT WAS THE WRONG BATTERY INSTALLED AND IT BELONGS TO A B737-700. CONTRIBUTING FACTORS: 1) FAILURE ON MY PART TO VERIFY OR RECOGNIZE THE WRONG PART NUMBER. 2) STORES ISSUING WRONG PRE-DRAWN PART FOR THE WRONG ACFT. 3) AN EXPERIENCED CO-WORKER FAILED TO RECOGNIZE THE WRONG PART NUMBER. 4) COMPANY PARTS COMPATIBILITY SYS FAILED TO FILTER THE WRONG PART NUMBER WHEN I ENTERED THE LOG PAGE INTO THE SYS. CORRECTIVE ACTION: REMOVAL AND REPLACEMENT OF THE WRONG BATTERY. FILED AN ASRS RPT. PERCEPTION: I THOUGHT THAT I INSTALLED THE CORRECT PART AND FAILED TO DOUBLECHK THE BATTERY PART NUMBER BECAUSE I RELIED ON STORES AND MY EXPERIENCED AVIONICS CO-WORKER TO DO THE RIGHT THING.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.